Notes

// reading liquid flow rate using Seeeduino and Water Flow Sensor from Seeedstudio.com
// Code adapted by Charles Gantt from PC Fan RPM code written by Crenn @thebestcasescenario.com
// http:/themakersworkbench.com http://thebestcasescenario.com http://seeedstudio.com
#define hallsensor d4
volatile int NbTopsFan; //measuring the rising edges of the signal
int Calc;
//int hallsensor = 4; //The pin location of the sensor

void rpm () //This is the function that the interupt calls
{
NbTopsFan++; //This function measures the rising and falling edge of the hall effect sensors signal


}
// The setup() method runs once, when the sketch starts
void setup() //
{
pinMode(hallsensor, OUTPUT); //initializes digital pin 2 as an input
Serial.begin(9600); //This is the setup function where the serial port is initialised,


attachInterrupt(0, rpm, RISING); //and the interrupt is attached
}
// the loop() method runs over and over again,
// as long as the Arduino has power
void loop ()
{
NbTopsFan = 0; //Set NbTops to 0 ready for calculations
sei(); //Enables interrupts
delay (1000); //Wait 1 second
cli(); //Disable interrupts
Calc = (NbTopsFan * 60 / 7.5); //(Pulse frequency x 60) / 7.5Q, = flow rate in L/hour


Serial.print (Calc, DEC); //Prints the number calculated above
Serial.print (" L/hourrn"); //Prints "L/hour" and returns a new line
}